Supplemental Guarantor Financial Information - Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	$ 270,275	$ 256,553	$ 188,553
Additions to property and equipment	(125,882)	(142,349)	(109,909)
Acquisitions, net of cash acquired	(22,669)	(103,874)	(226,972)
Proceeds from sale of assets and businesses	9,348	36,661
Net cash used in investing activities	(139,203)	(209,562)	(336,881)
Proceeds from borrowings under revolving credit facility	235,368	452,670	127,657
Repayments of borrowings under revolving credit facility	(311,362)	(499,551)	(61,539)
Proceeds from borrowings of long-term debt			250,000
Repayment of long-term debt			(200,000)
Debt issuance, modification and redemption costs			(14,746)
Payment of contingent consideration			(517)
Proceeds from exercises of stock options	673	1,107	810
Additional tax benefit related to share-based compensation	338	1,985	4,739
Repurchase of common shares	(3,959)	(4,731)	(7,156)
Net cash (used in) provided by financing activities	(78,942)	(48,520)	99,248
Effect of exchange rate changes on cash	(4,893)	(4,049)	(5,984)
Net increase (decrease) in cash and cash equivalents	47,237	(5,578)	(55,064)
Cash and cash equivalents as of beginning of period	26,297	31,875	86,939
Cash and cash equivalents as of end of period	73,534	26,297	31,875
Consolidation Eliminations
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities		370	(20)
Additions to property and equipment		(370)	20
Investment in subsidiary			102,220
Funding of intercompany notes payable, net			51,803
Net cash used in investing activities		(370)	154,043
Repayments of intercompany notes payable			(51,803)
Issuance of common shares			(102,220)
Net cash (used in) provided by financing activities			(154,023)
Parent
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	(1,106)
Proceeds from exercises of stock options	526
Additional tax benefit related to share-based compensation	681
Net cash (used in) provided by financing activities	1,207
Net increase (decrease) in cash and cash equivalents	101
Cash and cash equivalents as of end of period	101
Issuer
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	60,033	(12,180)	1,463
Investment in subsidiary			(51,110)
Funding of intercompany notes payable, net			(51,803)
Net cash used in investing activities			(102,913)
Proceeds from borrowings under revolving credit facility	198,826	379,400	127,657
Repayments of borrowings under revolving credit facility	(255,727)	(446,085)	(60,266)
Proceeds from borrowings of long-term debt			250,000
Repayment of long-term debt			(200,000)
Debt issuance, modification and redemption costs			(14,746)
Proceeds from intercompany notes payable	248
Repayments of intercompany notes payable		81,286
Proceeds from exercises of stock options	147	1,107	810
Additional tax benefit related to share-based compensation	(343)	1,985	4,739
Repurchase of common shares	(3,959)	(4,731)	(7,156)
Net cash (used in) provided by financing activities	(60,808)	12,962	101,038
Net increase (decrease) in cash and cash equivalents	(775)	782	(412)
Cash and cash equivalents as of beginning of period	782		412
Cash and cash equivalents as of end of period	7	782
Guarantors
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	98,033	164,345	123,255
Additions to property and equipment	(70,468)	(86,283)	(57,434)
Investment in subsidiary			(51,110)
Funding of intercompany notes payable, net		(750)
Acquisitions, net of cash acquired	(17,512)	(80,503)	(165,433)
Net cash used in investing activities	(87,980)	(167,536)	(273,977)
Repayments of borrowings under revolving credit facility			(4)
Proceeds from intercompany notes payable	(14,430)
Repayments of intercompany notes payable			35,829
Payment of contingent consideration			(201)
Issuance of common shares			51,110
Net cash (used in) provided by financing activities	(14,430)		86,734
Net increase (decrease) in cash and cash equivalents	(4,377)	(3,191)	(63,988)
Cash and cash equivalents as of beginning of period	6,200	9,391	73,379
Cash and cash equivalents as of end of period	1,823	6,200	9,391
Non-Guarantors
Condensed Cash Flow Statements, Captions [Line Items]
Net cash (used in) provided by operating activities	113,315	104,018	63,855
Additions to property and equipment	(55,414)	(55,696)	(52,495)
Funding of intercompany notes payable, net		750
Acquisitions, net of cash acquired	(5,157)	(23,371)	(61,539)
Proceeds from sale of assets and businesses	9,348	36,661
Net cash used in investing activities	(51,223)	(41,656)	(114,034)
Proceeds from borrowings under revolving credit facility	36,542	73,270
Repayments of borrowings under revolving credit facility	(55,635)	(53,466)	(1,269)
Proceeds from intercompany notes payable	14,182
Repayments of intercompany notes payable		(81,286)	15,974
Payment of contingent consideration			(316)
Issuance of common shares			51,110
Net cash (used in) provided by financing activities	(4,911)	(61,482)	65,499
Effect of exchange rate changes on cash	(4,893)	(4,049)	(5,984)
Net increase (decrease) in cash and cash equivalents	52,288	(3,169)	9,336
Cash and cash equivalents as of beginning of period	19,315	22,484	13,148
Cash and cash equivalents as of end of period	$ 71,603	$ 19,315	$ 22,484